Grammar fix

deep understanding

good knowledge

To know a subject or situation very well, including all the important details and reasons behind it.

collocationB2common

Hear it in context

Notice where the phrase sounds natural.

She has a deep understanding of how the human brain works.study
In my opinion, teachers should help students develop a deep understanding of the subject, not just memorize facts.IELTS speaking

Pattern: have/gain/develop a deep understanding (of something)

WrongShe has a deep understanding about the topic.

RightShe has a deep understanding of the topic.

'Understanding OF' — not 'about'.

Patternhave/gain/develop a deep understanding (of something)

Choose the version that sounds natural in speech.

Stiff He possesses a profound comprehension of the subject.

Natural He's got a deep understanding of the subject.

'Profound comprehension' is stiff; 'deep understanding' is the natural collocation.

Words that usually travel with it.

A 'basic understanding' means you only know the main points, while a 'deep understanding' means you know the details and reasons.